Field of the Disclosure
The present disclosure generally relates to compensating bails.
Description of the Related Art
In wellbore construction and completion operations, a wellbore is formed to access hydrocarbon-bearing formations (e.g., crude oil and/or natural gas) by the use of drilling. Drilling is accomplished by utilizing a drill bit that is mounted on the end of a drill string. To drill within the wellbore to a predetermined depth, the drill string is often rotated by a top drive or rotary table on a surface platform or rig, and/or by a downhole motor mounted towards the lower end of the drill string. After drilling to a predetermined depth, the drill string and drill bit are removed and a section of casing is lowered into the wellbore. An annulus is thus formed between the string of casing and the formation. The casing string is hung from the wellhead. A cementing operation is then conducted in order to fill the annulus with cement. The casing string is cemented into the wellbore by circulating cement into the annulus defined between the outer wall of the casing and the borehole. The combination of cement and casing strengthens the wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons.
Drill strings and casing strings are typically assembled by screwing together threaded joints end to end. As the joints are screwed together, allowance must be made for longitudinal displacement of the couplings as one is rotated relative to the other. Such displacement is accounted for using a thread (aka joint) compensator. Several prior art compensators are not designed to support an entire string of joints and/or do not inhibit or prevent undesirable movement of such joints within a derrick, particularly unwanted movement of a top end of a stand of joints in a derrick. One such system uses a compensator disposed between a travelling block and a typical elevator. A cable or cables are interposed between the compensator and the elevator. If a stand of multiple joints is lifted with such a system, it is possible for the top of the stand to whip around in the derrick due to the freedom of movement permitted by the cable(s).
When a joint compensator is used to support only one joint, once the single joint has been moved in and connected to a string that hangs from the slips in the rotary table, the joint compensator must be disconnected and moved out of the way, then a lifting elevator is connected to the string below the travelling block to support the entire string. Single joint compensators also cannot be used with a top drive, since an accidental overpull can result during a break out operation when the weight of an entire string is inadvertently applied to the compensator.